The world supply of edible fish and molluscs will run out if the patterns of harvesting these food sources keep on going at their present rate, according to a world-wide study published by scientists in five countries.

In an article published in the journal "Science," these investigators predict that 90% (ninety percent) of the species of fish and molluscs harvested from our seas will be exhausted toward the end of the first half of this century.

Even now, we have lost 90% of our annual harvest of more than a fourth of these species, according to Boris Worm, the principal author of the article and a professor at the Delhousie University in Halifax, Canada. "The loss of this important source of protein for our population is very well documented," he said. "And its rate of loss is continuously accelerating."

Worm and his team of researchers say, however, that it is possible to reverse this tendency if we (1) modify our current methods of fishing to make them more sustainable, (2) create marine sanctuaries where the different species of fish can gradually replenish themselves, and (3) reduce the rate of pollution of the shores of our seas.

"But if the environment that sustains these fish is destroyed or if the water of our seas is poisoned," said Heike Lotze, a marine ecologist at Delahousie University, "these marine species will become extinct."

Naturally in the case of such a biological disaster, other species of life will evolve after millions of years to fill these empty ecological niches, but this rate will be too slow to save the human race, whose population, at the current rate of demographic expansion, will increase by 3,000,000,000 (three billion) people in a few decades. And it will be more and more difficult to keep our world population alive with the loss of this source of food and others that will be reduced at an alarming rate with the progressive average-temperature increase in our atmosphere, which is now becoming more and more obvious.